{"id":"CVE-2026-98864","state":"PUBLISHED","title":"sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task\n\nebf1ccff79c4 (\"sched_ext: Fix ops.dequeue() semantics\") moved the final\nops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the\ncustody update and ops.dequeue() precede it. A task can thus be found on a\nDSQ while still SCX_OPSS_DISPATCHING.\n\nThe dequeue and core-sched pick paths wait for the state to clear in\nops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs\nops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed.\nThe dispatcher's final store then overwrites it with SCX_OPSS_NONE and\nfinish_dispatch() drops every later dispatch of the task.\n\nWait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for\nreenqueue, the same way ops_dequeue() does.","publishedAt":"2026-10-18T15:51:25.532Z","updatedAt":"2026-10-19T09:26:58.668Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d","status":"affected","lessThan":"43457bf6550044c40bd6d3fcdf9ea66f5a55d139","versionType":"git"},{"version":"ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d","status":"affected","lessThan":"7de9a6fb44eae4f05e68c805d58b9c618815adfa","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/sched/ext/ext.c","kernel/sched/ext/internal.h","kernel/sched/ext/sub.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/sched/ext/ext.c","kernel/sched/ext/internal.h","kernel/sched/ext/sub.c"]}],"references":["https://git.kernel.org/stable/c/43457bf6550044c40bd6d3fcdf9ea66f5a55d139","https://git.kernel.org/stable/c/7de9a6fb44eae4f05e68c805d58b9c618815adfa"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98864.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98864","state":"PUBLISHED","datePublished":"2026-10-18T15:51:25.532Z","dateUpdated":"2026-10-19T09:26:58.668Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.377Z"},"containers":{"cna":{"title":"sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task\n\nebf1ccff79c4 (\"sched_ext: Fix ops.dequeue() semantics\") moved the final\nops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the\ncustody update and ops.dequeue() precede it. A task can thus be found on a\nDSQ while still SCX_OPSS_DISPATCHING.\n\nThe dequeue and core-sched pick paths wait for the state to clear in\nops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs\nops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed.\nThe dispatcher's final store then overwrites it with SCX_OPSS_NONE and\nfinish_dispatch() drops every later dispatch of the task.\n\nWait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for\nreenqueue, the same way ops_dequeue() does."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d","status":"affected","lessThan":"43457bf6550044c40bd6d3fcdf9ea66f5a55d139","versionType":"git"},{"version":"ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d","status":"affected","lessThan":"7de9a6fb44eae4f05e68c805d58b9c618815adfa","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/sched/ext/ext.c","kernel/sched/ext/internal.h","kernel/sched/ext/sub.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/sched/ext/ext.c","kernel/sched/ext/internal.h","kernel/sched/ext/sub.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/43457bf6550044c40bd6d3fcdf9ea66f5a55d139"},{"url":"https://git.kernel.org/stable/c/7de9a6fb44eae4f05e68c805d58b9c618815adfa"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:26:58.668Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}